Maintaining data integrity is an important part of information systems. When a user makes changes to data stored on a system, the user often modifies a copy of the data. When the user wants to save the changes, a system will often save the entire copy of the data to which the user has access, particularly if the data is part of a user-defined object. However, if the user is accessing a large amount of data, saving the entire copy may consume a large amount of resources.
In the drawings, like reference numbers generally indicate identical or similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.